Using Apps Script to get the day of the month for a cell with a date in it

Question

This returns a date Logger.log(sht.getRange(1,1).getValue()) How do I get the day of the month for that cell?

I tried Logger.log(sht.getRange(1,1).getValue()).date() and Logger.log(date(sht.getRange(1,1).getValue())) neither worked

Answer 1

ALTERNATE SOLUTION

Using your sample spreadsheet as a guideline, and based on one of your comments:

I am trying to hide all the rows before the first day of a month and all the days after the end of a month. I have done this another way but I am trying to learn about how to correctly use this getDate function as part of making my whole sheet cleaner.

You can try to follow this:

1. First, I've created separate functions for hiding and showing rows depending on the day of the month. One thing that I noticed on your sample sheet is that, for weekdays there are 4 rows populated for different times, while on weekends there are 6 rows populated.
2. As such, I've taken those into consideration in creating the two functions which executes by using the hideRows() and showRows() function, respectively.
3. Now, we can go to the main function, where the other functions will be called to perform the hiding (or unhiding) of rows. For this, I've also used a separate date variable, which calls the current date to compare with the other dates on the spreadsheet, and check if they are to be shown or hidden.

You can refer to the following scripts for your reference:

• The two functions for hiding and showing rows:

  function hideRows(date, index) {
    var ss = SpreadsheetApp.getActive();
    var sht = ss.getActiveSheet();
    // checks if the date is a weekend
    if (date[index].getDay() == 0 || date[index].getDay() == 6) {
      sht.hideRows(index + 2, 6);   // you can change the 2nd integer depending on the number of rows populated on weekends
      return index += 5;
    }
    // if the date is a weekday
    else {
      sht.hideRows(index + 2, 4);   // you can change the 2nd integer depending on the number of rows populated on weekdays
      return index += 3;
    }
  }
  
  function unhideRows(date, index) {
    var ss = SpreadsheetApp.getActive();
    var sht = ss.getActiveSheet();
    // checks if the date is a weekend
    if (date[index].getDay() == 0 || date[index].getDay() == 6) {
      sht.showRows(index + 2, 6);   // you can change the 2nd integer depending on the number of rows populated on weekends
      return index += 5;
    }
    // if the date is a weekday
    else {
      sht.showRows(index + 2, 4);   // you can change the 2nd integer depending on the number of rows populated on weekdays
      return index += 3;
    }
  }
  

• The main function:

  function myFunction() {
    var ss = SpreadsheetApp.getActive();
    var sht = ss.getActiveSheet();
    var row = 2;
    var date = sht.getRange(row, 1, sht.getLastRow() - (row - 1), 1).getValues().flat();
    var today = new Date();
  
    for (i = 0; i < date.length; i++) {
      // a ternary operator that checks if 
      // a) the date on the spreadsheet is in the same month as today's date (to show the rows), or;
      // b) hide all rows before the 1st date of the next month, or dates after the end of the previous month
      date[i] != "" ? date[i].getMonth() == today.getMonth() || (date[i].getMonth() == today.getMonth() + 1 && date[i].getDate() == 1) ? i = unhideRows(date, i) : i = hideRows(date, i) : false;
    }
  }
  

For the ternary operator, its logic is similar to this if-else statement:

if (date[i] != "") {
    if(date[i].getMonth() == today.getMonth() || (date[i].getMonth() == today.getMonth()+1 && date[i].getDate() == 1)){
      unhideRows(date,i);
    }
    else{
      hideRows(date,i);
    }
  }

REFERENCES

• getDay()
• getMonth()
• getDate()
• hideRows() and showRows()